The gen 2-2.5 Tundras with the 5.7 are beasts, it is damn tough motor. Apparently, it is listed as a 500K-1 million mile rated motor by Toyota. I love my '12, other than the thirsty gas mileage. They are easy to work on, and I don't question the reliability on long trips, just do a good pre-game and be proactive when they need some TLC. I would be cautious with the 4.7, it is an excellent motor, but it is an interference motor, so if the belt breaks, the motor is toast. That said, my LX470 had the 4.7, just change the belt, water pump and seals every 80k miles and they run a LOOOONG time. The 5.7 has a timing chain, so it's a non-issue. I would look at a '14 or newer though, few things I didn't know when I bought my '12, namely, that '14 and newer had the option for a 38 gallon fuel tank, the older ones only have a 26 gallon tank.Lumped all together.......most likely not. In general, yes, things break down over time. But some just seem to go and go and go for decades. I've been blessed and fortunate I guess.
I don't really fall into the "mileage" thing though. The vehicles are either in good running shape or they aren't. But ya, if they start nickel and diming you constantly with repairs.....it might be time to let them go.
I'll admit it.......I've been looking at Tundra's.......but not new ones. Mostly 2015 and prior. But I definitely don't get rid of what I already have (with any kind of gear)......until I've had a chance to figure out whether I'm going to fully like the newer items. I have a ton of stuff that's 30-40+ years old that I still use all the time. Because I haven't found anything that works better to replace those items with. I'm pretty picky.